Replacing soil pipe stack and vent (plus running from new toilet location)

15 Jun 2016
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United Kingdom

Can someone please confirm the below as I can not seem to find the right section and my local Building control officer department seems all on holiday.

**This is not a thread about adding a toilet, it covers only moving the existing one from outrigger wall to ide return wall.**

Hopefully picture will help (key below)

red crosses are removals

Blue lines is indicating new line of stack/vent pipe

Green is indicating new 3m external run of soil pipe to branch
white circles are 90 bends (with access points?)

White Cross is proposal of branching stack/vent pipe

Existing and single toilet at property is on outrigger wall under obscured glass window.
The existing soil pipe stack and vent at the rear of the house (outrigger wall) is very dated and I'd like to replace it for more modern materials etc. at the same time I am rejigging internal about of bathroom.

1. If the old stack is being replaced just under ground level (vertically) before the existing clay rest bend to the sewers this is a job that does not require building control - correct?

2. The existing vent pipe does not go vertically upwards but at 45% for a metre before heading to the roof line - is this due to the close proximity of one of the bathroom windows?
Is there a way I can just carry the line u through past the bathroom window (as the soil pipe follows the same line past the kitchen window?

3. Bend question (number of)
I'm looking to move the toilet internally to the 'side return wall' and run the 'new' soil pipe externally for 3 metres (so ~9cm drop)
As this is the only toilet in the property being moved from one wall to the next, I'm guessing that its ok to branch this into the proposed straight run of stack and vent pipe.
(Forget the existing rain water/guttering in the picture this will move)
There will be 2 x 90 degree bends in this, one coming out of the wall by the moved toilet and then at the end of the property.
At these 2 bends I would need access points?

4. The existing rain water and sink pipe go to a separate ground (next to the soil pipe) , whereby after its own trap it feeds directly into the same shared sewer.
The existing bath/shower waste already joins the soil pipe.
The rain water off the roof I'm definitely keeping separate into the sewers,

but in theory as the bath/shower waste is already attached to the soil pipe can I add the sink waste as well without issue or BC involvement?



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